#include <bits/stdc++.h>

void solve() {
    int h, w;
    std::cin >> h >> w;
    auto encode = [&](int i, int j) {
        return i * w + j;
    };
    std::vector a(h, std::vector<int>(w));
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            std::cin >> a[i][j];
        }
    }
    std::vector graph(h * w, std::vector<int>());
    const int DI[] = {1, 0, -1, 0};
    const int DJ[] = {0, 1, 0, -1};
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            int k = encode(i, j);
            for (int d = 0; d < 4; d++) {
                int ni = i + DI[d];
                int nj = j + DJ[d];
                if (ni < 0 || ni >= h || nj < 0 || nj >= w) continue;
                if (a[i][j] >= a[ni][nj]) continue;
                int nk = encode(ni, nj);
                graph[k].push_back(nk);
            }
        }
    }
    std::vector<int> dp(h * w, -1);
    auto dfs = [&](auto self, int u) -> int {
        if (dp[u] != -1) return dp[u];
        dp[u] = 1;
        for (int v: graph[u]) {
            dp[u] = std::max(dp[u], self(self, v) + 1);
        }
        return dp[u];
    };
    int ans = 0;
    for (int i = 0; i < h * w; i++) {
        ans = std::max(ans, dfs(dfs, i));
    }
    std::cout << ans << '\n';
}

int main() {
    std::cin.tie(0)->sync_with_stdio(0);
    std::cout << std::fixed << std::setprecision(16);
    int t = 1;

    while (t--) solve();
}